The working principle of a disposable negative pressure drainage device is based on pressure difference, which enables the extraction of liquid and tissue debris from the wound site, as follows:
1. Create a negative pressure environment
      The device mainly consists of a drainage tube, a negative pressure source, and a collection container. Negative pressure source is a key component that generates pressure difference, and common types include manual negative pressure ball and electric negative pressure pump. The manual negative pressure ball is repeatedly squeezed by medical personnel to expel the air inside the ball. After releasing it, the ball will rely on its own elasticity to restore its original state, thereby forming negative pressure inside; An electric negative pressure pump, after being powered on, uses a motor to drive an air extraction device to correctly, continuously, and stably extract air, reducing the air pressure inside the system.
2. Drainage process
      One end of the drainage tube is inserted into the patient's wound or surgical site, and the other end is connected to a collection container. When the negative pressure source is activated, the pressure inside the drainage system quickly drops below the external atmospheric pressure, and a suction force is generated at the wound site due to the pressure difference. The exudate, blood, necrotic tissue fragments, etc. inside the wound will be "sucked" into the collection container through a soft and resilient drainage tube.
3. Maintain drainage status
      As long as the negative pressure source continues to work, the pressure difference will persist, and the drainage process will also continue. Medical staff can adjust the negative pressure value based on the actual wound condition, such as wound size, exudate volume, healing stage, etc. For smaller and shallower wounds, using lower negative pressure can prevent damage to newly formed tissue; For large-scale and deep wounds, a large negative pressure is required to quickly and efficiently clean the exudate, prevent accumulation and infection, and promote better wound healing. Throughout the process, the transparent collection container facilitates medical staff to observe the status of the drainage fluid at any time, assisting in determining the progress of wound recovery.